Question

Name the four extraembryonic membranes.

Answer 1

Extraembryonic membranes are the layers enclosing the embryo inside the uterus. There are fourlayers: the amnion, yolk sac, allantois, and chorion. The amnion is the innermost layer, enclosing the embryo in the amnion fluid, which protects it from mechanical stress.

Answer 2

Most birds reptiles embryo’s are covered in extraembryonic membranes which are developing within a shelled egg. The extraembryonic layers are of four types;

• The amnion which provides protection to the embryo enclosed in a sac having amniotic fluid.

• The yolk sac having yolk which is the mixture of proteins and lipoproteins is the source of food until the egg hatches.  

• The chorion is present on the inner shell surface and is permeable to gases aiding in exchange of O2 and CO2 between the environment and embryo.

• The allantois is used to store metabolic waste products of the embryo mainly uric acid and it also helps in gaseous exchange.